Cotton (Gossypium hirsutum L.) is an importantfiber cash crop,but its root traits related to phosphorus (P) acquisition,including mycorrhizal root traits,are poorly understood.Eight cotton varieties bred in northweste...Cotton (Gossypium hirsutum L.) is an importantfiber cash crop,but its root traits related to phosphorus (P) acquisition,including mycorrhizal root traits,are poorly understood.Eight cotton varieties bred in northwestern China that were released between 1950 and 2013 were grown in pots with or without one arbuscular mycorrhizal fungal (AMF) species(Funneliformis mosseae) at three P supply levels (0,50 and 300 mg P as KH_(2)PO_(4)kg^(-1)).Eleven root traits were measured and calculated after 7 wk of growth.The more recent accessions had smaller root diameters,acquired less P and produced less biomass,indicating an (inadvertent) varietal selection for thinner roots that provided less cortical space for AMF,which then increased the need for a high P fertilizer level.At the two lower P levels,the mycorrhizal plants acquired more P and produced more biomass than non-mycorrhizal plants (3.2 vs.0.9 mg P per plant;1.8 vs.0.9 g biomass per plant at P_(0);14.5 vs.1.7 mg P per plant;and 4.7 vs.1.6 g biomass per plant at P_(50)).At the highest P level,the mycorrhizal plants acquired more P than non-mycorrhizal plants (18.8 vs.13.4 mg per P plant),but there was no difference in biomass (6.2 vs.6.3 g per plant).At the intermediate P level,root diameter was significantly positively correlated with shoot biomass,P concentration and the P content of mycorrhizal plants.The results of our study support the importance of the outsourcing model of P acquisition in the root economics space framework.Inadvertent varietal selection in the last decades,resulting in thinner roots and a lower benefit from AMF,has led to a lower productivity of cotton varieties at moderate P supply (i.e.,when mycorrhizal,the average biomass of older varieties 5.0 g per plant vs.biomass of newer varieties 4.4 g per plant),indicating the need to rethink cotton breeding efforts in order to achieve high yields without very high P input.One feasible way to solve the problem of inadvertent varietal selection for cotton is to be aware of the trade-offs between the root do-it-yourself strategy and the outsourcing towards AMF strategy,and to consider both morphological and mycorrhizal root traits when breeding cotton varieties.展开更多
Background： The cotton bollworm （Helicoverpa armigera） is one of cotton＇s most destructive insect pests in terms of yield and quality. Since 1997, China has grown commercially available transgenic Bacillus thuring...Background： The cotton bollworm （Helicoverpa armigera） is one of cotton＇s most destructive insect pests in terms of yield and quality. Since 1997, China has grown commercially available transgenic Bacillus thuringiensis （Bt） cotton. We aimed to investigate the variation in resistance of transgenic Bt cotton varieties to cotton bollworm in North China. Methods： Populations of cotton bollworm were monitored from 2008 to 2015 in environments where Bt cotton was planted adjacent to other non Bt crops. The study included 197 Bt cotton varieties planted in 42 counties/locations in three provinces （Hebei, Shandong and Henan） of North China, which were evaluated through field investigations, bioassays, and enzyme linked immunosorbent assays （ELISA）. Results： The average number of cotton bollworms never exceeded the action threshold （10 larvae per 100 cotton plants）, however, their number reached 19.55 per 100 cotton plants in 2011. The ratios of damaged plants to total Bt cotton stem tips, buds, and bolls was low except in 2010, when the ratios reached 1.82%, 2.09%, and 10.63%, respectively. The results of bioassay showed that the corrected mortality were higher at the second generation cotton bollworm stage than the third and fourth germination stages. Totally, Bt protein content declined sharply at the seedling stage from 2008 to 2015. Conclusions： This study indicated that almost all Bt cotton varieties were capable to effectively control the populations of cotton bollworm in North China.展开更多
Background Bt technology has played significant role in controlling bollworms and increasing cotton yield in earlier days of its introduction,a subsequent decline in yield became apparent over time.This decline may be...Background Bt technology has played significant role in controlling bollworms and increasing cotton yield in earlier days of its introduction,a subsequent decline in yield became apparent over time.This decline may be attributed to various environmental factors,pest dynamics,or combination of both.Therefore,the present biophysical survey and questionnaire were designed to evaluate the impact of Bt cotton on bollworms management and its effect on reducing spray costs,targeting farmers with varied landholdings and educational backgrounds.Additionally,data on farmers'cultivated varieties and the prevalence of bollworms and sucking insects in their fields were recorded.Subsequently,about eleven thousand cotton samples from farmer fields were tested for Cry1Ac,Cry2Ab and Vip3A genes by strip test.Results In this analysis,83% of the farmers planting approved varieties believe that Bt technology control bollworms,while 17% hold contradictory views.Similarly,among farmers cultivating unapproved varieties,77% agree on effectiveness of Bt technology against bollworms,while 23% disagree.On the other hand,67% of farmers planting approved varieties believe that Bt technology does not reduce spray costs,while 33% agree with the effectiveness.Similarly,78% of farmers cultivating unapproved varieties express doubt regarding its role to reduce spray costs,while 22% are in favour of this notion.Differences in opinions on the effectiveness of Bt cotton in controlling bollworms and reducing spray cost between farmers planting unapproved and approved varieties may stem from several factors.One major cause is the heavy infestation of sucking insects,which is probably due to the narrow genetic variation of the cultivated varieties.Additionally,the widespread cultivation of unapproved varieties(21.67%)is also an important factor to cause different opinions on the effectiveness of Bt cotton.Conclusion Based on our findings,we propose that the ineffective control of pests on cotton crop may be attributed to large scale cultivation of unapproved varieties and non-inclusion of double and triple transgene technologies in country's sowing plan.On the basis of our findings,we suggest cotton breeders,regulatory bodies and legislative bodies to discourage the cultivation of unapproved varieties and impure seed.Moreover,the adoption of double and triple Bt genes in cottons with a broad genetic variation could facilitate the revival of the cotton industry,and presenting a promising way forward.展开更多
The development and wide application of genetic transformation for cotton improvement are restrained by the unresolved problem of genotype dependence in regeneration in vitro.High embryogenic and regenerative potentia...The development and wide application of genetic transformation for cotton improvement are restrained by the unresolved problem of genotype dependence in regeneration in vitro.High embryogenic and regenerative potential have been obtained for limited number of Coker type genotypes。展开更多
[Objective] The aim of this study was to characterize the national regis- tered varieties selected from cotton regional trials in Yangtze River Valley （YaRV） in recent years. [Method] Cotton cultivar classification ...[Objective] The aim of this study was to characterize the national regis- tered varieties selected from cotton regional trials in Yangtze River Valley （YaRV） in recent years. [Method] Cotton cultivar classification and comprehensive evaluation index were set up based on national cotton registration standard. GGE biplot method was adopted to analyze the correlation of major breeding target characters of 53 national registered cotton varieties in cotton regional trials in YaRV during 1981-2012. According to the shift of check cultivars in cotton regional trials in the past, the cotton regional trial practice since 1981 was divided into five periods. The dynamic of cultivar type＇s proportion and the evaluation index scores was analyzed across the five periods. [Result] There existed intricate interrelationship among cotton breeding target traits, which constrained it necessary to construct indices for com- prehensive evaluation of cotton varieties. The dynamic of cultivar types in the five periods indicated that type II varieties emerged since Simian 3 period and then its proportion decreased gradually; type Ⅲ varieties maintained a certain proportion in each period and kept on the rise overall; type Ⅳvarieties occupied the majority pro- portion of registered cultivars before 1993, but a minor proportion since Simian 3 period. On the other side, the change trend of the evaluation index demonstrated that the varieties registered before 2003 did not pass the qualified line at present. The peak scores appeared in the varieties registered during 2004-2008. The scores of the varieties registered after 2009 were only slightly over the qualified line. [Conclusion] More attention should be paid to the improvement and evaluation of micronaire, so as to guide the simultaneous development of high yielding and fiber quality in cotton breeding and registration procedure in YaRV.展开更多
The year of 2013 is a typical rainy and poor sunshine year, and the monthly sunshine hours from May to October were all lower than the average, which from July to September was only 69.3%,71.1% and 56.2% of average, r...The year of 2013 is a typical rainy and poor sunshine year, and the monthly sunshine hours from May to October were all lower than the average, which from July to September was only 69.3%,71.1% and 56.2% of average, respectively. In cotton-wheat system 10 cotton varieties （lines） were planted to select the most suitable varieties for cotton-wheat system in rainy and poor sunshine years through investigating cotton growing traits in 2013. The results showed that in cotton-wheat system the vegetative growth of cotton was mainly from late June to middle July especially in rainy and poor sunshine years. And with the increase of the cotton growth period the peak of vegetative growth delayed, the ratio of the autumn bolls increased, and the ratio of pre-frost yield decreased. In all the varieties unginned cottonyield of Zhongmiansuo 50 with shorter growth period, higher rate of summer bolls and better fiber quality, seed yield reached 3 814.1 kg/hm2, higher than that of other varieties （lines） significantly, and the rate of pre-frost yield reached 83.4%, which was the most suitable variety for cotton-wheat system in rainy and poor sunshine years.展开更多
Genotype and plant type affect photosynthetic production by changing the canopy structure in crops.To analyze the mechanism of action of heterosis and plant type on canopy structure in cotton(Gossypium hirsutum L.),we...Genotype and plant type affect photosynthetic production by changing the canopy structure in crops.To analyze the mechanism of action of heterosis and plant type on canopy structure in cotton(Gossypium hirsutum L.),we had selected two cotton hybrids(Shiza 2,Xinluzao 43) and two conventional varieties(Xinluzao 13,Xinluzao 33) with different plant types in this experiment.We studied canopy characteristics and their correlation with photosynthesis in populations of different genotypes and plant types during yield formation in Xinjiang,China.Canopy characteristics including leaf area index(LAI),mean foliage tilt angle(MTA),canopy openness(DIFN),and chlorophyll relative content(SPAD).The results showed that LAI and SPAD peak values were higher and their peak values arrived later,and the adjustment capacity of MTA during the flowering and boll-forming stages was stronger in Xinluzao 43,with the normal-leaf,pagoda plant type,than these values in other varieties.DIFN of Xinluzao 43 remained between0.09 and 0.12 during the flowering and boll-forming stages,but was lower than that in the other varieties during the boll-opening stage.Thus,these characteristics of Xinluzao 43 were helpful for optimizing the light environment and maximizing light interception,thereby increasing photosynthetic capability.The photosynthetic rate and photosynthetic area were thus affected by cotton genotype as changes in the adjustment range of MTA,increases in peak values of LAI and SPAD,and extension of the functional stage of leaves.Available photosynthetic area and canopy light environment were affected by cotton plant type as changes in MTA and DIFN.Heterosis expression and plant type development were coordinated during different growth stages,the key to optimizing the canopy structure and further increasing yield.展开更多
In the article the research of cotton seeds for the purpose of increasing the fiber in the enterprise is investigated, separated from the mass of the derivatives of ginning of fibrous seeds by means of effective clean...In the article the research of cotton seeds for the purpose of increasing the fiber in the enterprise is investigated, separated from the mass of the derivatives of ginning of fibrous seeds by means of effective cleaning and sorting on the mesh surface.展开更多
Thirty-six Chinese cottons were investigated for their physical properties using ASTM stand-ard test methods. Conventional methods using stelometer, fibrograph, and micronaireinstrumentation provided physical properti...Thirty-six Chinese cottons were investigated for their physical properties using ASTM stand-ard test methods. Conventional methods using stelometer, fibrograph, and micronaireinstrumentation provided physical properties of tenacity, elongation, length, and fineness. Varietaland regional variations were examined. The Chinese cottons were compared with upland varietiesof American cottons grown across the country. In general, American cottons were stronger, butperhaps a little shorter than Chinese cottons. American cottons were no more mature on the aver-age, and they had lower elongations than did the Chinese cottons. The American cottons alsotended toward higher length uniformity than those varieties grown in China. High yarn strengthwas strongly favored by American cottons.展开更多
We compared the ground-dwelling beetle assemblages under four scenarios in which transgenic Bt（Cry 1Ac） cotton（33B）,transgenic Bt（Cry 1Ac）＋CpTI cotton（SGK321）,conventional cotton（33）,conventional cotton（Sh...We compared the ground-dwelling beetle assemblages under four scenarios in which transgenic Bt（Cry 1Ac） cotton（33B）,transgenic Bt（Cry 1Ac）＋CpTI cotton（SGK321）,conventional cotton（33）,conventional cotton（Shiyuan 321） in North China.During the survey in two years（2009-2010）,24 ground beetle species were captured with pitfall traps in 20 plots which included five replicates for each cotton type.No significant difference was observed in the number of ground beetle species captured,activity density,evenness and Shannon-Wiener diversity among the four cotton varieties.Chlaenius posticalis was less abundant in transgenic Bt＋CpTI cotton（SGK321） fields than its conventional cotton（Shiyuan 321）,but more abundant in transgenic Bt cotton（33B） fields compared with its conventional cotton（33）.There was no significant difference for other abundant species between in transgenic cotton and in conventional cotton fields.Based on non-metric multidimensional scaling（NMDS） analysis,ground-dwelling beetle assemblages were similar in transgenic and conventional cotton over the two years,but the ground-dwelling beetle assemblages in transgenic cotton 33 B significantly differed from that in the conventional cotton（strain 33） in 2010.No strong evidence that the transgenic cotton effect on ground-dwelling beetle assemblages was found in this study.展开更多
基金financially supported by the National Natural Science Foundation of China(32272807 and U1703232)supported via project from State Key Laboratory of North China Crop Improvement and Regulation(NCCIR2021ZZ-1)。
文摘Cotton (Gossypium hirsutum L.) is an importantfiber cash crop,but its root traits related to phosphorus (P) acquisition,including mycorrhizal root traits,are poorly understood.Eight cotton varieties bred in northwestern China that were released between 1950 and 2013 were grown in pots with or without one arbuscular mycorrhizal fungal (AMF) species(Funneliformis mosseae) at three P supply levels (0,50 and 300 mg P as KH_(2)PO_(4)kg^(-1)).Eleven root traits were measured and calculated after 7 wk of growth.The more recent accessions had smaller root diameters,acquired less P and produced less biomass,indicating an (inadvertent) varietal selection for thinner roots that provided less cortical space for AMF,which then increased the need for a high P fertilizer level.At the two lower P levels,the mycorrhizal plants acquired more P and produced more biomass than non-mycorrhizal plants (3.2 vs.0.9 mg P per plant;1.8 vs.0.9 g biomass per plant at P_(0);14.5 vs.1.7 mg P per plant;and 4.7 vs.1.6 g biomass per plant at P_(50)).At the highest P level,the mycorrhizal plants acquired more P than non-mycorrhizal plants (18.8 vs.13.4 mg per P plant),but there was no difference in biomass (6.2 vs.6.3 g per plant).At the intermediate P level,root diameter was significantly positively correlated with shoot biomass,P concentration and the P content of mycorrhizal plants.The results of our study support the importance of the outsourcing model of P acquisition in the root economics space framework.Inadvertent varietal selection in the last decades,resulting in thinner roots and a lower benefit from AMF,has led to a lower productivity of cotton varieties at moderate P supply (i.e.,when mycorrhizal,the average biomass of older varieties 5.0 g per plant vs.biomass of newer varieties 4.4 g per plant),indicating the need to rethink cotton breeding efforts in order to achieve high yields without very high P input.One feasible way to solve the problem of inadvertent varietal selection for cotton is to be aware of the trade-offs between the root do-it-yourself strategy and the outsourcing towards AMF strategy,and to consider both morphological and mycorrhizal root traits when breeding cotton varieties.
基金supported by the project of China Agriculture Research System(CARS-15-20)
文摘Background： The cotton bollworm （Helicoverpa armigera） is one of cotton＇s most destructive insect pests in terms of yield and quality. Since 1997, China has grown commercially available transgenic Bacillus thuringiensis （Bt） cotton. We aimed to investigate the variation in resistance of transgenic Bt cotton varieties to cotton bollworm in North China. Methods： Populations of cotton bollworm were monitored from 2008 to 2015 in environments where Bt cotton was planted adjacent to other non Bt crops. The study included 197 Bt cotton varieties planted in 42 counties/locations in three provinces （Hebei, Shandong and Henan） of North China, which were evaluated through field investigations, bioassays, and enzyme linked immunosorbent assays （ELISA）. Results： The average number of cotton bollworms never exceeded the action threshold （10 larvae per 100 cotton plants）, however, their number reached 19.55 per 100 cotton plants in 2011. The ratios of damaged plants to total Bt cotton stem tips, buds, and bolls was low except in 2010, when the ratios reached 1.82%, 2.09%, and 10.63%, respectively. The results of bioassay showed that the corrected mortality were higher at the second generation cotton bollworm stage than the third and fourth germination stages. Totally, Bt protein content declined sharply at the seedling stage from 2008 to 2015. Conclusions： This study indicated that almost all Bt cotton varieties were capable to effectively control the populations of cotton bollworm in North China.
基金supported by Punjab Agriculture Research Board,Grant numbers PARB No.890received research support from Punjab Agriculture Board。
文摘Background Bt technology has played significant role in controlling bollworms and increasing cotton yield in earlier days of its introduction,a subsequent decline in yield became apparent over time.This decline may be attributed to various environmental factors,pest dynamics,or combination of both.Therefore,the present biophysical survey and questionnaire were designed to evaluate the impact of Bt cotton on bollworms management and its effect on reducing spray costs,targeting farmers with varied landholdings and educational backgrounds.Additionally,data on farmers'cultivated varieties and the prevalence of bollworms and sucking insects in their fields were recorded.Subsequently,about eleven thousand cotton samples from farmer fields were tested for Cry1Ac,Cry2Ab and Vip3A genes by strip test.Results In this analysis,83% of the farmers planting approved varieties believe that Bt technology control bollworms,while 17% hold contradictory views.Similarly,among farmers cultivating unapproved varieties,77% agree on effectiveness of Bt technology against bollworms,while 23% disagree.On the other hand,67% of farmers planting approved varieties believe that Bt technology does not reduce spray costs,while 33% agree with the effectiveness.Similarly,78% of farmers cultivating unapproved varieties express doubt regarding its role to reduce spray costs,while 22% are in favour of this notion.Differences in opinions on the effectiveness of Bt cotton in controlling bollworms and reducing spray cost between farmers planting unapproved and approved varieties may stem from several factors.One major cause is the heavy infestation of sucking insects,which is probably due to the narrow genetic variation of the cultivated varieties.Additionally,the widespread cultivation of unapproved varieties(21.67%)is also an important factor to cause different opinions on the effectiveness of Bt cotton.Conclusion Based on our findings,we propose that the ineffective control of pests on cotton crop may be attributed to large scale cultivation of unapproved varieties and non-inclusion of double and triple transgene technologies in country's sowing plan.On the basis of our findings,we suggest cotton breeders,regulatory bodies and legislative bodies to discourage the cultivation of unapproved varieties and impure seed.Moreover,the adoption of double and triple Bt genes in cottons with a broad genetic variation could facilitate the revival of the cotton industry,and presenting a promising way forward.
文摘The development and wide application of genetic transformation for cotton improvement are restrained by the unresolved problem of genotype dependence in regeneration in vitro.High embryogenic and regenerative potential have been obtained for limited number of Coker type genotypes。
基金Supported by Key Special Project for Breeding and Cultivation of GMO Varieties(2012ZX08013015)Jiangsu Agriculture Science and Technology Innovation Fund(JASTIF,CX-12-5035)~~
文摘[Objective] The aim of this study was to characterize the national regis- tered varieties selected from cotton regional trials in Yangtze River Valley （YaRV） in recent years. [Method] Cotton cultivar classification and comprehensive evaluation index were set up based on national cotton registration standard. GGE biplot method was adopted to analyze the correlation of major breeding target characters of 53 national registered cotton varieties in cotton regional trials in YaRV during 1981-2012. According to the shift of check cultivars in cotton regional trials in the past, the cotton regional trial practice since 1981 was divided into five periods. The dynamic of cultivar type＇s proportion and the evaluation index scores was analyzed across the five periods. [Result] There existed intricate interrelationship among cotton breeding target traits, which constrained it necessary to construct indices for com- prehensive evaluation of cotton varieties. The dynamic of cultivar types in the five periods indicated that type II varieties emerged since Simian 3 period and then its proportion decreased gradually; type Ⅲ varieties maintained a certain proportion in each period and kept on the rise overall; type Ⅳvarieties occupied the majority pro- portion of registered cultivars before 1993, but a minor proportion since Simian 3 period. On the other side, the change trend of the evaluation index demonstrated that the varieties registered before 2003 did not pass the qualified line at present. The peak scores appeared in the varieties registered during 2004-2008. The scores of the varieties registered after 2009 were only slightly over the qualified line. [Conclusion] More attention should be paid to the improvement and evaluation of micronaire, so as to guide the simultaneous development of high yielding and fiber quality in cotton breeding and registration procedure in YaRV.
基金Supported by Project Supported by National Science and Technology Ministry(2013BAD05B00)National Cotton Industry System(CARS-18-21)~~
文摘The year of 2013 is a typical rainy and poor sunshine year, and the monthly sunshine hours from May to October were all lower than the average, which from July to September was only 69.3%,71.1% and 56.2% of average, respectively. In cotton-wheat system 10 cotton varieties （lines） were planted to select the most suitable varieties for cotton-wheat system in rainy and poor sunshine years through investigating cotton growing traits in 2013. The results showed that in cotton-wheat system the vegetative growth of cotton was mainly from late June to middle July especially in rainy and poor sunshine years. And with the increase of the cotton growth period the peak of vegetative growth delayed, the ratio of the autumn bolls increased, and the ratio of pre-frost yield decreased. In all the varieties unginned cottonyield of Zhongmiansuo 50 with shorter growth period, higher rate of summer bolls and better fiber quality, seed yield reached 3 814.1 kg/hm2, higher than that of other varieties （lines） significantly, and the rate of pre-frost yield reached 83.4%, which was the most suitable variety for cotton-wheat system in rainy and poor sunshine years.
基金support of the National Natural Science Foundation of China (U1203283)the National Key Technology R&D Program of China (2014BAD09B03)the Natural Science Foundation of Hebei (C2015301051)
文摘Genotype and plant type affect photosynthetic production by changing the canopy structure in crops.To analyze the mechanism of action of heterosis and plant type on canopy structure in cotton(Gossypium hirsutum L.),we had selected two cotton hybrids(Shiza 2,Xinluzao 43) and two conventional varieties(Xinluzao 13,Xinluzao 33) with different plant types in this experiment.We studied canopy characteristics and their correlation with photosynthesis in populations of different genotypes and plant types during yield formation in Xinjiang,China.Canopy characteristics including leaf area index(LAI),mean foliage tilt angle(MTA),canopy openness(DIFN),and chlorophyll relative content(SPAD).The results showed that LAI and SPAD peak values were higher and their peak values arrived later,and the adjustment capacity of MTA during the flowering and boll-forming stages was stronger in Xinluzao 43,with the normal-leaf,pagoda plant type,than these values in other varieties.DIFN of Xinluzao 43 remained between0.09 and 0.12 during the flowering and boll-forming stages,but was lower than that in the other varieties during the boll-opening stage.Thus,these characteristics of Xinluzao 43 were helpful for optimizing the light environment and maximizing light interception,thereby increasing photosynthetic capability.The photosynthetic rate and photosynthetic area were thus affected by cotton genotype as changes in the adjustment range of MTA,increases in peak values of LAI and SPAD,and extension of the functional stage of leaves.Available photosynthetic area and canopy light environment were affected by cotton plant type as changes in MTA and DIFN.Heterosis expression and plant type development were coordinated during different growth stages,the key to optimizing the canopy structure and further increasing yield.
文摘In the article the research of cotton seeds for the purpose of increasing the fiber in the enterprise is investigated, separated from the mass of the derivatives of ginning of fibrous seeds by means of effective cleaning and sorting on the mesh surface.
基金Information presented at the 1989 Cotton Improvement Conference, Nashville, Tennessee USA
文摘Thirty-six Chinese cottons were investigated for their physical properties using ASTM stand-ard test methods. Conventional methods using stelometer, fibrograph, and micronaireinstrumentation provided physical properties of tenacity, elongation, length, and fineness. Varietaland regional variations were examined. The Chinese cottons were compared with upland varietiesof American cottons grown across the country. In general, American cottons were stronger, butperhaps a little shorter than Chinese cottons. American cottons were no more mature on the aver-age, and they had lower elongations than did the Chinese cottons. The American cottons alsotended toward higher length uniformity than those varieties grown in China. High yarn strengthwas strongly favored by American cottons.
基金supported by the the Special Program for New Transgenic Variety Breeding of the Ministry of Science and Technology,China(2013ZX08012-005 and 2014ZX08012-005)
文摘We compared the ground-dwelling beetle assemblages under four scenarios in which transgenic Bt（Cry 1Ac） cotton（33B）,transgenic Bt（Cry 1Ac）＋CpTI cotton（SGK321）,conventional cotton（33）,conventional cotton（Shiyuan 321） in North China.During the survey in two years（2009-2010）,24 ground beetle species were captured with pitfall traps in 20 plots which included five replicates for each cotton type.No significant difference was observed in the number of ground beetle species captured,activity density,evenness and Shannon-Wiener diversity among the four cotton varieties.Chlaenius posticalis was less abundant in transgenic Bt＋CpTI cotton（SGK321） fields than its conventional cotton（Shiyuan 321）,but more abundant in transgenic Bt cotton（33B） fields compared with its conventional cotton（33）.There was no significant difference for other abundant species between in transgenic cotton and in conventional cotton fields.Based on non-metric multidimensional scaling（NMDS） analysis,ground-dwelling beetle assemblages were similar in transgenic and conventional cotton over the two years,but the ground-dwelling beetle assemblages in transgenic cotton 33 B significantly differed from that in the conventional cotton（strain 33） in 2010.No strong evidence that the transgenic cotton effect on ground-dwelling beetle assemblages was found in this study.
